Question 1127750
{{{x}}}=hours of TV watched per day

{{{y}}} number of sit-ups a person can do


{{{y=ax+b}}}

if given: 
{{{x=11h}}}
{{{a=-1.341}}}
{{{b=32.234}}}

{{{y=-1.341*11+32.234}}}
{{{y=17.483}}}



You actually do not need {{{r}}} to find {{{y}}}. Also, when they say "use this", their meaning is "use this formula".

{{{y = ax + b}}}

That's a formula for some variable {{{y}}}. In other words, if you know what {{{x}}} is, then you can find its associated value of {{{y}}}. But, what does{{{ y}}} represent? If I told you,for example, that{{{ y=27.5}}} when {{{x = 5.7}}}, what is the meaning?

They gave you the values of the constants {{{a}}} and {{{b}}}.

Anytime you're given the value of a constant, you may substitute the given value for the symbol anywhere that symbol appears.

Finally, they gave you a value for{{{ x}}}. They want to know what will {{{y}}} be for that value of {{{x}}}?


why {{{r=-0.896}}}?

We should compute the correlation coefficient only for data that follows a linear pattern or to determine the degree to {{{which}}} a data set is {{{linear}}}. 
If the data exhibits a nonlinear pattern, the correlation coefficient for a linear regression is meaningless. 
To get a sense for the relationship between the value of {{{ r}}}  and the graph of the data.

The correlation coefficient is a value, {{{ r}}} , between {{{-1}}} and {{{1}}}.

{{{r>0}}}  suggests a positive ({{{increasing}}}) relationship
{{{r<0 }}} suggests a negative ({{{decreasing}}}) relationship

The closer the value is to {{{0}}}, the {{{more}}} {{{scattered}}} the data.
The closer the value is to {{{1}}} or {{{-1}}}, the {{{less}}}{{{ scattered}}} the data is.

 You have {{{r=-0.896}}}. This value is very close to {{{-1}}}, which suggests a strong {{{decreasing }}}{{{linear}}} relationship and the data is {{{less}}}{{{ scattered}}}.